Replace: What's the difference between %ARTIST% and ARTIST?

I've long been puzzled by htis. If you look at the Replace Quick Action Fields avaliable in the Feild drop down you will se %ARTIST% and ARTIST listed. Empirically I've the experience that ARTIST works and %ARTIST% remains a mystery. On the off chance this isn't what you see, I offer an image of what I see attached.

My question is, what is the difference between these three seemingly arbitrary top % bounded tags and the rest of the list? Is it something peculiar to my local configuration and something I did and forgot or does everyone see this?

Looks like bad input from yourself, which has been remembered in the history list.
Such erroneous entries can be deleted manually.
The list can also be resetted entirely.

Additionally read there ...
Working with multiple value tags


Hey, not sure why I didn't see that. Yes a reset of the fields list got rid of the % items and yes perhaps they were just memories of my typing dumb stuff a long time ago when I first started using MP3tag. Thanks!